"This is a first time venture for Greens Farms Academy," explained Christopher Hisey, a strings teacher and "Chess" conductor. "We are performing a concert version ... with the entire music and theater departments and in addition, the American Chamber Orchestra (which Hisey conducts), members from the Norwalk Community Chorale and several faculty and staff members in the Grand Chorus. So it really is a school-wide, community endeavor.

"It's a huge undertaking, but it's going to be fantastic," he said, adding that the piece is a "rock opera with gorgeous symphonic and choir tones throughout."

Both performances will be at Coyle Gym at Greens Farms Academy, 35 Beachside Ave., Westport; 203-256-0717. Tickets will be sold only at the door. The Friday night performance ($10) is considered a "preview" and will be slightly less formal than the Saturday night performance ($15).

Fifty years of song

The Fairfield County Chorale's Executive Director John Parkinson said Saturday's event will feature Mozart's "Vesperae solennes de Confessores" ..."made up of six glorious choral melodies that only Mozart could have created." Also slated are works by Mendelssohn and Beethoven.

"The finale of the concert will be Vivaldi's wonderful `Gloria' ... a longtime favorite (that) has been the signature piece performed by the chorale on tour, where it has enthralled audiences around the world," Parkinson said.

And as a highlight, the chorale will be joined by the group's alumni chorus, which "includes our emeritus members who have 10 years service or more and represent a vital piece of the chorale's heritage. These members include charter members and past presidents. Alumni will travel from as far away as California to participate in this event," he explained.

The Greater Bridgeport Youth Orchestras' Sunday concert will feature all five GBYO ensembles at the Klein, 910 Fairfield Ave., Bridgeport.

Hisey, who also is music director for the nonprofit student organization, will conduct the Principal Orchestra in the Lalo cello concerto as well as Kodaly's Intermezzo (dedicated to former GBYO conductor Dorothy Straub). Highlights from Bernstein's "West Side Story" and "Japanese Maple," by college student Alyssa Rodriguez, of Newtown, also are on the program. (Alyssa's piece had been scheduled to premiere at the GBYO's Winter Concert, which was canceled because of snow.)

Also performing will be members of the group's Symphony Orchestra, Concert Orchestra, String Orchestra and Wind Ensemble. The GBYO's 240-plus members, chosen by competitive auditions every fall, are in grades five-12 and reside in 27 communities in Fairfield and New Haven counties.

In addition, the GBYO's KEYS String Ensemble, a group of Bridgeport youth new to instrumental performance, conducted by Erica Messina, will make its debut with "The Russian Music Box," by Soon Hee Newbold and "Simple Square Dance," by Dorothy Straub.